Python

Python_EX-004. 10 way data read from a file

X25WLK 2025. 1. 21. 10:54

 


No. Method Code Example Pros Cons
1 read() # to read the entire file

with open('filename.txt', 'r') as file:
    data = file.read()
    print(data)

- Simple 
- Easy to use
- Not suitable for large files
(memory-intensive)
2 readline() # to read one line at a time

with open('filename.txt', 'r') as file:
    line = file.readline()
    while line:
        print(line.strip())
        line = file.readline()

- Suitable for large files
- Allows processing
  line-by-line
- Slightly complex
- Requires handling
  end-of-file manually
3 readlines()
#  to read all lines into a list

with open('filename.txt', 'r') as file:
    lines = file.readlines()
    for line in lines:
        print(line.strip())

- Easy to use
- Stores all lines in a list
- Not suitable for large files
(memory-intensive)
4 for loop # to read line by line

with open('filename.txt', 'r') as file:
    for line in file:
        print(line.strip())

- Simple & clean code
- Suitable for large files
- Slightly less intuitive
for beginners
5 seek()
# to read specific parts

with open('filename.txt', 'r') as file:
    file.seek(10)
    data = file.read(20)
    print(data)

- Allows random access
to specific parts of the file
- Useful for binary files
- Requires knowledge
of file structure
- More complex code
6 Reading a file # reading a file
# as a list comprehension


with open('filename.txt', 'r') as file:
    lines = [line.strip() for line in file]
    print(lines)

- Concise & expressive code
- Combines reading & processing
- Not suitable for large files (memory-intensive)
7 Path
from pathlib
# Path from pathlib

from pathlib import Path

data = Path('filename.txt').read_text()
print(data)

- Modern & user-friendly API
- Integrates well with
other pathlib functionalities
- Requires pathlib
 (Python 3.4+)
- Limited to text files
8 numpy
# tread data
# (for structured data)


import numpy as np

data = np.loadtxt('filename.txt')
print(data)

- Efficient for numerical data
- Provides powerful data
  manipulation capabilities
- Requires numpy library
- Suitable mainly
  for numerical data
9 pandas: # to read data
# (for tabular data)


pimport pandas as pd

df = pd.read_csv('filename.txt')
print(df)

- Excellent for tabular data
- Provides powerful
 data analysis tools
Requires pandas library
- More complex
 than basic file reading
10 csv module
# to read CSV files

import csv

with open('filename.txt', 'r') as file:
    reader = csv.reader(file)
    for row in reader:
        print(row)

- Built-in module (no additional installation required)
- Suitable for CSV files
- Limited to CSV files
- Requires handling of CSV-specific issues
(e.g., delimiters, quoting)

 

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